J-20 fighter’s 1m-aperture radar better than F-35: analyst

J-20 stealth fighter is equipped with China’s latest airborne active phased array radar, which is at least one generation advanced than the active phased array radars equipped on J-10C and J-16. The airborne active phased array radars of the three fighters, J-20 stealth fighter, J-10C and J-16, were developed by the famous Nanjing China Electronics Group. Not surprisingly, at present, China has not released the performance data of the airborne radars carried by these three fighters.

However, in 2015, “Science Chinese” website hosted by the China Association for Science and Technology introduced an article about Lin Youquan, chief scientist of China Electronics Group, and mentioned that he led development of China’s first X-band active phased array airborne fire control. In the development of radar, the radar won the first prize of National Defense Science and Technology Progress Award in 2009 and the second prize of National Science and Technology Progress Award in 2010. It is reported that the technical level of this radar is comparable to that of AN/APG-77 active phased array radar on US F-22 fighter, laying a solid technical foundation for the development of China’s new generation of fighter fire control radar. China’s X-band airborne active phased array radar is the world’s leading airborne fire control radar. Currently, only the United States, Japan and some European countries are using it on fighter aircrafts. Russia only showed similar equipment on the Moscow Air Show and Zhuhai Air Show in 2014, but the passive phased array radar was still used on Su-35 fighter.

Fortunately, in addition to developing airborne radar for the Chinese Air Force’s fighter aircraft, the institute also developed KLJ-7A active phased array radar for Pakistan Air Force’s JF-17 Block-3 fighter. In order to attract favor of the Pakistan Air Force and more customers, the institution introduced the radar in detail at the Zhuhai Air Show last year.

The data shows that KLJ-7A active phased array radar has a hole diameter of only 600 mm, but it integrates more than 1000 T/R components. The maximum detection distance of an air target of 1 square meter is 170 kilometers, and the performance is much better than the huge N011M passive phased array radar used on India’s Su-30MKI fighter, while the US APG-83 radar, also known as the low-cost AESA radar designed for F-16V, uses a large number of technologies from F-35’s APG-81 radar.

An important description of KLJ-7A active phased array radar by the institute was that KLJ-7A radar is smaller than APG-81 radar equipped with F-35 stealth fighter, but its combat capability is comparable to that of APG-81 radar. It is not difficult to imagine that since the performance of KLJ-7A radar used for export is so great, that of the radar equipped on J-20 stealth fighter is naturally worth looking forward to.

At Zhuhai Air Show 2018, China also exhibited an AESA active phased array radar called LKF601E, which has the characteristics of small size, light weight, convenient replacement and high reliability. According to the booth data, it’s a X-band, multi-function radar with enhanced fire control capability which can detect fighters 170 kilometers away, and can track 15 targets at the same time. The maximum search range for the sea reaches 220 kilometers.

With such excellent data of performance, people cannot help but want to count its TR components, so the major Chinese military forums instantly become geometric classrooms… how many TRs from this side, how many TRs are the angles…and the final number was amazing. There should be around 864 TR components, even better than advanced APG-77 radar of the United States, even similar to APG-81.

According to military analyst Keluo Liaofu, another proof of the great performance of the active phased array radar equipped on J-20 stealth fighter is its large diameter. In simple terms, an important indicator of active phased array radar is the number of T/R (transmit/receive) components. The greater the number of T/R components, the higher the detection range and accuracy of the radar. Therefore, stealth fighters sometimes have bigger heads. At this point, the US F-22A and F-35 stealth fighters are relatively disadvantaged.

Since J-20’s nose is huge, it is expected that the aperture of the active phased array radar of J-20 stealth fighter may reach 1 meter. The integration of more than 2000 T/R components should not be a problem. And take the number of components and the detection distance of T/R of KLJ-7A radar as a reference, the performance geometry of J-20 stealth fighter airborne radar should be more or less clear.